This invention relates to a technology for improving the precision of stream data processing.
Stream data processing by which high rate data is processed in real time is attracting attention against the background of increased need to analyze in real time successive pieces of information that are generated at a high rate and take action instantaneously in response to a critical event in automated stock transaction, faster traffic information processing, click stream analysis, and the like.
With stream data processing, which is a versatile middleware technology applicable to various types of data processing, real-world data can be reflected on a business in real time while dealing with rapid changes to business environment that give no time to build a system for each individual case.
A stream processed in stream data processing is time-series data in which tuples, i.e., pieces of time-stamped data, arrive at a stream data processing server in succession. A user of stream data processing defines a rule for monitoring the stream as a query, and the stream data processing server converts the query definition into a query graph.
A query graph is a directed graph in which the unit of processing called an operator is a node and a tuple queue between operators is an edge. An input stream is processed in the manner of a data flow by putting individual tuples that make up the input stream through the stream's query graph.
Being data flow-type processing, this processing can process a query graph that is divided into multiple stages in parallel in the manner of a pipe line with the use of a plurality of computer resources. U.S. Pat. No. 8,391,164 B2 and WO 2014/041673 A1 are known as technologies that use parallel processing to process stream data output from a plurality of data sources.
The technology disclosed in U.S. Pat. No. 8,391,164 B2 combines a plurality of pieces of stream data before processing the stream data. The technology disclosed in WO 2014/041673 A1 provides an independent work area for each of a plurality of pieces of stream data.